|Location||Super Gold Card|
Some programs make use of the QL’s ability to support a second screen (on a standard QL this is normally stored at $28000 (hex) - it overwrites the system variables which are moved to another area in memory). You can therefore see why it is important never to make assumptions about the location of the screen or system variables in memory (use SCREEN or SYS_BASE instead).
Minerva extends this second screen even further, allowing you to operate the computer in two-screen mode, with programs being started up on one of two screens (thus allowing you to have completely different displays on each screen) see MODE. The main problem with this second screen is that it slows down the operation of the computer and therefore if you do not intend to use the second screen, you may wish to disable it.
You can disable the second screen with the command SCR2DIS - this setting will be stored in memory by the Gold Card and the second screen will henceforth always be disabled.
Some programs (mainly games) will not work properly with the second screen disabled.
SCR2EN re-enables the second screen again.